Recent legislative and regulatory changes require that a local exchange carrier (LEC) unbundle certain network elements and services and offer use of those elements and services to other carriers for resale to end users. In one required implementation, the LEC will sell the other carrier an unbundled port on an end office switch and allow the other carrier to become a competing local exchange carrier (CLEC) by reselling services of the switch to end users having local loops which connect to the end office switch. Those statutory and regulatory changes also specify that customized routing is required for both unbundled switching and for resale. Customized routing is the term used in the regulations for routing calls made in the local exchange carrier (LEC) switch to locations other than those that exist today. The primary applications are for unbundlers and resellers to have operator (0+, 0-) calls and directory assistance calls (411/555) routed to their own platforms. Other types of calls could possibly be applicable as well, but the 0+/0-/411 calls are the ones in most immediate demand.
This type of customized routing in an interconnection environment represents a capability that currently does not exist in the network architecture of LECs. The currently used switches in the LEC public switched telephone networks were not designed with this functionality in mind. The capability does not exist and the switches are not readily adaptable to provide customized routing. This applies to all of the predominantly deployed switches (5ESS, 1AESS, EWSD, and DMS-100) from three major switch manufacturers, Lucent Technologies (formerly AT&T), Nortel, and Siemens.
One prospective unbundler and reseller has suggested use of line class codes (LCCs) to accomplish this purpose. However, any implementation of customized routing using LCCs would require use of an excessive number of such codes and would produce other serious problems. Not only is there a limit to the capacity of the switch regarding the number of LCCs that could be physically provisioned, managing the new operational environment is at least as critical. The provisioning and maintenance systems that support the LEC's services cannot be ignored. These systems allow telephone services to be ordered, provisioned, monitored, repaired, and billed; they are an essential element in contributing to the quality of service enjoyed today by the public LEC's customers.
Without incorporating new LCCs into the operations systems that support services, severe problems would have to be expected in provisioning services. Manual provisioning would require human intervention and complex lookups that involve locating the correct code in a table of thousands. Such a process would be prone to both error and delay resulting in service degradation. It is for this reason that today's process is mechanized. In an environment with considerably more codes, a mechanized process would be even more important.
The line class code approach would use existing switch resources in a manner that was never intended. Such an application is untested and to some degree would have unknown consequences if deployed on any meaningful scale. Even the proponent of this approach has indicated that LCCs would be an interim and limited workaround which would need to be reversed once a longer term solution could be developed.
Another proposal for coping with the problem has been the possible use of an Advanced Intelligent Network (AIN) common channel signaling (CCS) solution. However, this is not feasible in view of the fact that, while the AT&T 1AESS switch has AIN capability, it will not apply AIN type processing to 0 calls. In that switch, the 0 number routing functionality takes precedence over all other types of call processing, including AIN processing.
The patent literature suggests various approaches to more or less analogous problems.
U.S. Pat. No. 5,550,912, issued Aug. 27, 1996 to Akinpelu et al., and U.S. Pat. No. 5,475,749, issued Dec. 12, 1995 to Akinpelu et al., assigned to AT&T Corporation, disclose specialized call processing in an interexchange carrier (IXC) network to route calls via a LEC and a CLEC or competing local exchange carrier (termed a `competing access provider` or `CAP` in these patents).
In one aspect of the Akinpelu et al. call processing, the switch of the IXC network serving as the egress point for a call, checks the area code (NPA) and office code (OC or NXX) of the dialed number to determine if `exception` routing is necessary, i.e., to determine if the destination station lies in a region served by a LEC and one or more CLECs. If no exception routing is necessary (LEC only), the egress switch routes the call through the LEC carrier switch in the normal manner. However, if exception routing is necessary, the egress switch checks the last four digits of the called number against an exception table to determine if the particular number is served through a CLEC switch or a LEC switch. The table look up can utilize translation tables in the egress switch or tables in a remote database. If the last four digits from the dialed number are listed in the exception table, then the egress switch routes the call through the CLEC's switch. If the last four digits from the dialed number are not listed in the exception table, then the egress switch routes the call through the LEC's switch. If the called customer receives service from both a CLEC and a LEC, the egress switch will route the call through the CLEC switch unless all trunks between the IXC egress switch and the CLEC switch are busy, in which case the egress switch routes the call via the LEC switch.
The Akinpelu et al. Patents also disclose a specialized translation and routing process at the ingress switch of the IXC network. In some cases, a different egress switch serves a CLEC than serves a LEC. For such a case, the ingress switch queries a database. The database identifies the called customer's preferred local exchange carrier and possibly an alternate carrier. Based on the local carrier identification (LEC or CLEC), the ingress switch routes the call through the appropriate egress switch. Data identifying the IXC egress switch, the preferred and alternate carriers and the identity of the terminating switches of the preferred and alternate carriers are transmitted via CCS messages to the egress switch, to eliminate the need for further translation by the egress switch.
U.S. Pat. No. 5,473,681, issued Dec. 5, 1995 to B. Waring Partridge, III, assigned to AT&T Corporation, relates to processing of telephone calls through two or more carriers. Such calls may involve a local exchange carrier and an interexchange carrier, a wireless carrier and a local carrier, or any combination of multiple local exchange carriers and interexchange carriers. In a mobile telephone call, for example, a wireless carrier may route the call through an interexchange carrier to a distant local exchange carrier to complete the call.
A second carrier is preselected as a default primary interexchange carrier (PIC). However, the caller also may select the second carrier on a per call basis by dialing an interexchange access code.
Partridge, III teaches that, for each call in which a telecommunications carrier code specifying a particular carrier is supplied by a caller, the network of the local service provider routing such a call transmits to the selected IXC carrier network an indication that the carrier code was dialed by the caller. The local service provider network may also transmit an indication, if applicable, that the entered carrier code is not the default carrier code. The local service provider network transmits these indications regarding second carrier selection as SS7 messages or portions thereof. The second or interexchange carrier may use the carrier selection indications, for example, to control provision of certain special services on the respective calls.
U.S. Pat. No. 5,333,184, issued Jul. 26, 1994 to Doherty et al., assigned to AT&T Bell Laboratories, discloses a system for recording the `primary interexchange carrier` identification for the called party. The interexchange carrier typically processes calls from calling parties who have PIC'd that carrier for their long distance services. By recording the PIC of the called party as well, the interexchange carrier can offer special billing treatments for calls from one subscriber to any other one of that carrier's own subscribers.
U.S. Pat. No. 5,311,572, issued May 10, 1994 to Albert Friedes and Om P. Mahajan, assigned to AT&T Bell Laboratories, discloses a system for processing a database-queried call using the call processing capabilities of a carrier's database as well as a subscriber's database. The carrier's database is a routing database. The subscriber's database contains prestored programs and calling party identification related information including background of the caller.
U.S. Pat. No. 4,565,903, issued Jan. 21, 1986 to Douglas H. Riley, assigned to AT&T Bell Laboratories, relates to call routing in a multi-carrier environment, in particular to the selection of an interexchange carrier and the routing of a call to the selected carrier.
A subscriber is allowed to presubscribe any carrier by having information identifying that carrier entered in a memory associated with the subscriber's terminal link. The subscriber can then have interexchange calls routed to that carrier without taking any additional steps to select or specify the carrier. The subscriber can select any available carrier on a per-call basis by transmitting, e.g., dialing, signals identifying the desired carrier. Thus, a subscriber may prefer one carrier for certain calls and another for other calls. A caller can complete interexchange calls without having to select a carrier by identifying in a second memory a default carrier for calls for which no carrier is specified.
A carrier for an originating terminal link's telephone call is selected by examining dialing signals or the like received over the terminal link to determine whether they include signals identifying a carrier separate from the signals identifying the call destination-identifying. If a carrier cannot be so identified, the contents of a memory associated with the terminal link are examined to determine whether they identify a carrier, typically based on a presubscription to the carrier's services. A second memory can be examined to determine whether they identify a carrier (default) for use when even the memory associated with the terminal link does not identify a carrier. When a carrier cannot be identified, a request is made over the terminal link that a carrier be identified. Once a carrier is identified, the local exchange network attempts to connect the call to that carrier.
U.S. Pat. No. 5,517,562, issued May 14, 1996 to Von K. McConnell, assigned to Independent Telecommunications Network, Inc. of Overland Park, Kans., discloses an intelligent network type system utilizing the networks of independent telephone companies and other telecommunication service providers to offer centralized, custom subscriber services. McConnell provides a centralized network Service Control Point (SCP) and an associated Service Creation Environment (SCE). Individual service providers have service creation terminals of various types, and the SCE terminals are linked to a service creation server. The server also communicates with the network SCE. Participating service providers may each operate a dedicated SCP linked to the network SCP via a high speed data link. Customized services are created via the diverse SCE terminals, and appropriate records are established in one or more of the SCPs to control actual provision of services.
U.S. Pat. No. 5,550,911, issued Aug. 27, 1996 to Bhagat et al., assigned to Lucent Technologies Inc., which is the telecommunications equipment company recently spun off from AT&T, discloses call processing techniques for routing calls to an adjunct processor. The adjunct may connect to an originating switch (OSW), or the OSW may access a remote adjunct through a handoff switch (HSW) when the local adjunct is unavailable. The OSW maintains an automatic number identification (ANI) based trigger table. The OSW compares information relating to an incoming telephone call to the customer's trigger table to determine if the call requires processing via an adjunct. If an adjunct is required, the OSW determines the type of adjunct necessary, identifies an adjunct that is capable of processing the call and routes the call to the identified adjunct.
Once the call reaches the adjunct, the OSW or the HSW transfers information to the adjunct, including the ANI information relating to the particular call. The adjunct stores customer specific applications, and processes the call in accord with one such application selected in response to the call related information from the switch.
The adjunct may operate in a query mode to provide information to the switch without interaction with the caller, or the adjunct may interact with the caller using in-band communications. In the query mode, there is no voice connection to the adjunct. The switch is free to route the call upon completion of the query operation. In the interactive mode, the voice call is completed to the adjunct, so that the adjunct may send voice prompt messages and receive DTMF responses. Upon completion of an interactive operation, the adjunct transmits a release instruction to the switch. The release instruction may include a redirection request for transferring the call to an actual destination.